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Article Citation - WoS: 4Citation - Scopus: 4Simulation of Through-Hardening of Sae 52100 Steel Bearings - Part Ii: Validation at Industrial Scale(Wiley-v C H verlag Gmbh, 2016) Evcil, G. E.; Mustak, O.; Simsir, C.In this study, the material dataset presented in part I of this article is validated at industrial scale in batch through-hardening of bearing races. The material dataset acquired is implemented in a commercial heat treatment simulation software. Heat transfer coefficients for the oil and salt bath are determined by using a commercial standard quench probe. Zone temperatures and transfer times of the roller-belt furnace are measured directly from the system. Through-hardening of inner ring (IR) of 6813 bearing in oil and salt bath is simulated considering most of the industrial details. Finally, predicted dimensional changes are compared with the coordinate measurement results and a good agreement is achieved. It is concluded that determined material and process data, idealizations and simulation procedure can be considered "validated" for further improvement of the industrial process.Article Citation - WoS: 17Citation - Scopus: 26Process-Chain Simulation for Prediction of the Distortion of Case-Hardened Gear Blanks(Wiley-v C H verlag Gmbh, 2012) Simsir, C.; Hunkel, M.; Luetjens, J.; Rentsch, R.In this study, a process-chain simulation model is presented for the prediction of distortion of low-pressure gas carburised SAE 5120 (EN 20MnCr5) steel gear blanks. For this purpose, the evolution of the banded microstructure stemming from the continuous casting process was traced by computer simulations of subsequent shape rolling, forging and machining steps. Then, the simulated local orientation angles of the deformed banded microstructure are transferred to heat treatment simulation module as an input for the recently developed material model that exploits the Anisotropic Transformation Strain (ATS) concept to reproduce the dishing behaviour which cannot be reproduced by former models. The results indicate that the suggested procedure provides quite good predictions of the dishing directions and dishing-free cutting strategy, whereas; the dishing magnitude is predicted fairly reasonably considering large scatters in the experiments.Article Citation - WoS: 5Citation - Scopus: 6Effect of welding wire and groove angle on mechanical properties of high strength steel welded joints(Wiley-v C H verlag Gmbh, 2017) Evci, C.; Isik, H.; Macar, M.Mechanical properties of high strength steel welded joints strictly depend on the welding process, the filler material composition and the welding geometry. This study investigates the effects of using cored and solid welding wires and implementing various groove angles on the mechanical performance of weld joints which were fabricated employing the gas metal arc welding process. It was found that weld joints of low alloy, high strength steels using low alloy steel cored welding wires exhibited higher tensile strength than that of low alloy steel solid wire and chromium-nickel steel bare welding wire when the method of gas metal arc welding is employed. The effect of groove angle on the strength and toughness of V-groove and double V-groove butt-joints was investigated. V-groove joints, with higher tensile strength than double V-groove joints in the whole range of groove angles, were superior in toughness for small groove angles, but impact toughness values of both joints were comparable for large angles. The effect of heat input and cooling rate on the weld microstructure and weld strength was also investigated by performing thermal analysis employing the commercial software ANSYS. It was concluded that cooling rate and solidification growth rate determined the microstructure of the weld zone which had great consequences in regard to mechanical properties.Article Citation - WoS: 8Citation - Scopus: 10Simulation of Through-Hardening of Sae 52100 Steel Bearings - Part I: Determination of Material Properties(Wiley-v C H verlag Gmbh, 2016) Mustak, O.; Evcil, G. E.; Simsir, C.A complete material dataset for the simulation of through-hardening of SAE 52100 (DIN/EN 100Cr6, JIS SUJ2) steel was derived by a combination of experimental and theoretical/computational methods. In the experimental part, alpha/quenching and deformation dilatometry techniques are combined with density measurements, X-Ray diffraction, optical and scanning electron microscopy to determine temperature and phase dependent transformation kinetics parameters, thermal and transformation strains, flow curves and the transformation plasticity parameter. Thermal properties such as thermal conductivity, specific heat and enthalpy and elastic properties are acquired by thermodynamics based material property calculation method using a commercial software. For most of the material properties, the results were in good agreement with the literature, while the minor discrepancies are discussed considering the raw material, equipment used, testing and evaluation procedure. In Part II of this article, compiled material data is validated successfully in an industrial oil and salt-bath quenching of bearing races.
